Cyclodiene chlorosilane modified mineral pigment, polymer composition containing same, and method of making



March 1960 J. REHNER, JR.. ET AL 2,928,802

CYCLODIENE CHLOROSILANE MODIFIED MINERAL PIGMENT, POLYMER COMPOSITION CONTAINING SAME, AND METHOD OF MAKING Filed Dec. 1, 1955 STRESS PROPERTIES OF BUTYL RUBBER COMPOUNDS CONTAINING STANDARD AND CPD SICI3' MODIFIED HI SI'IC FILLER BEFORE AND AFTER HOT MILLING I I I I I I I MODIFIED Hi SiIC HEAT-TREATED ,4 700 MODIFIED HI'SiIC soo NOHEAT-TREATMENTJ) 50o STD. HiSIIC 300 MODULUS, X HEAT-TREATED LBS./IN.2

Ioo

I I I I I I 0 I0 20 4o so TIME OF CURE, MINUTES AT 307 F.

John Rehner, Jr. Herbert K. Wiese Inventors Albert M. GessIer By 2'. MM Attorney CYCLODIENE CHLGROSILANE MODIFIED MIN- ER-AL PIGMENT, POLYMER COMPOSITION CON- TAINING sAMnnNn nrrrnonor MAKING as, Rainier, 3n, Wsttieid, Herbert n. Wiesgand Aiber't G'e'ssler, Crantord, Nah, assignors to Esso Research 7 and Engineering Company, a corporation of Deiaware Application December 1; 195$, Serial No. 550,251

, 1e claims. (Cl. 260-415 This invention relates to a novelmethod of treating mi'neralpigments .and fillers such as hydrated silicas and aluminas in order to modify them so the resulting fillers will have improved'reinforcing properties when'conipounded into rubber, resins, paints, inks," etc. or other pigmentedcompositions.

Heretofore, somehydrated silicas and other materials have been reacted with someorganic-substitut'ed chlorosilanes inorder to give them modified properties. For instance, vinyl and cycl'ohexenyl trichlor'osilane have been used as such treating agents, and have accomplished certainefiects in modifying the properties of the treated silicas.

However, it has now been found,according to the present invention, that not only unexpectedly s'uperior results but also in srne=instances entirely diiferent 'kinds of results, may be obtained by treating the hydrated silicas,

clays, aluminas, etc. with a new and different type of organic halosilane; The treating agent used is' one having the general formula m n Zn-FZ-m where a is a cycloalkadienyl radical, m=1 to 2n+1', and

X is ahalogen having an atomic weight'a't least as high as that of chlorine, and 11:1 to or somewhat higher.

The preferred organo halosilane to be used is ing the general formula where m= l to 3, as in the formulae RSiCl-g, R SiCl R SiCl', etc., or mixtures thereof. Thera'dical R is preferably a cyclopentadienyl radical C II R may'also be the corresponding methyl cyclopentadienyl radical, or may be one of the corresponding cyclohexadienyl radicals. A preferred specific treating agent is cyclopentadienyl trichlorosilane, which has the graphic-formula:

Gsi G13 (Cs r) one havor generically One may also use:

. I; s a

'type'm'aterials', as 'well as corresponding radicals derived from the cyclopen'ta'diene" dimer. The actual cjhern'it':a1 preparation "of these 'cyclopent'adienyl halosil'ane's is not part of the present invention, but has "beendescribed in application Serial No. 367,758, filed July" 13 1953', by W ei s'eet al.,' the disclosures of "which are incorporated herein'by reference. a p

According to the pre'sen't'inventio'rhthe above-described cycloalkadienyl halosilanes are reacted withstiitable halosilane-reactive mineral pigments or fillers. Such pigment is preferably selected from the group consistingof at least partially hydrated silicas, aluminas, calcium silicates, and clays. I a a a The mineral fillers to be used may be selected from a fairly wide variety of inorganic min'eral pr'odiicts'"either consisting of or containing large amounts of silica alumina or other oxides or hydrated or partially hydrated derivatives thereof, or naturally occurring mineral deposits or synthetic material containing such substances along with other'inorganic elements or compounds, for instance, in addition to using finely divided silicas and aluminas perse, such as examples of various mineral fillers that may be used including the following:

The proportionsof mineral filler and si1aae -i.e., tne

organo 'halosilane)= to be used willyaryaccording' to the particular kind of cach -of inese'*materia1s v'vl'iiclr-is.

being used;- Nornizllly, howeve iftlie anions: or the silane should be aboufl to 15 by V /eight, preferably about 3 tol0'% by weight, based on the amouiit of the hydrated min'e'raifiller or pigment.

The treatment or modification-of thepignient with the silanemayj-be 'carrie'dfoutin various ways; One suitable method isto dissolve the silan'e, as, "for'instan'ce cyclope'nt'adien'yl tiichlorosilane in an inert solvent such as either an inerthydrocarbon liquid, e.g.'; parafiinic or naphthenic hydrocarbons, e.g.,- normal hexane-or heptane, cyclohexan'e, a refined kerosene fraction, etc., or an inert aromatic hydrocarbon solvent, e.g.,' benzene, toluene, xylene, or a mixed petroleum aromatic fraction suclr as Solvesso, having a'boiling range of about 200 to 275 F, or inert halogenated organic solvents such as carbon tetrachloride, tetrachlorethane, o-dichlorbenzene, etc. Then the pigment to be treated is added,-preferably gradu ally, to the resulting solution, at the desired reaction temperature which may be about'O' to C., preferab ly about 20 to60 'C., with suitable ag'tation and withfprovision' for removal or'disposal'of hydrogen enaride'becaus'e'it may be given on during the "reaction; Th resultingslurry should be stirred until the reaction is apparently complete.

This reaction is violent at first and'probably takes place immediately by'utilizing free water held on the "pigment. Theprobablereaction maybe represented bythe following general equation:

For instance, when Hi Sit, which is a fine particle hydrated silica dioxide, is added to a hexane solution of of the silica particles. This part of the reaction may be represented by the following equation:

o I l B ro- After the reaction has completely subsided or been completed to the desired extent, -the solvents may be evaporated off from the treated pigment, and the latter may be dried by any suitable means such as by air drying at 25 to 100 C. or by drying in a vacuum oven at about 25 to 80 C, The color either disappears completely or is greatly reduced in the dried treated pigment product, and therefore no 'difiiculty is encountered in subsequent use of such productinmaking compounded white rubber mixtures.

The cyclodiene-halosilane-modified hydrated pigments made as thus described above are useful for many different purposes, chief of which is for compounding with various liquid to solid base stocks, preferably unsaturated, which may be of a number of different types including rubbers, resins, plastics, paints, inks, etc. Examples of plastifiable solid base stocks'which may be used include as high styrene-low diene resins, or tripolymers such as one containing 30 to 50% by weight of styrene, 1 to of diolefin, and balance of mono-olefins such as isobutylene. Saturated resins with which the modified pigments may be compounded, though without ability to form bonded pigment-resin particles, include polystyrene, poly ethylene, polyvinyl chloride, styrene-isobutylene copolymers, and various other synthetic or natural resins. If desired, the halosilane may be reacted with the mineral filler directly during the compounding with rubber, resin or other material, though the hydrogen chloride liberated tends to causesome corrosion of metal equipment.

Butyl rubber is a synthetic high molecular rubbery copolymer of about 0.1 to by weight of a multiolefin of 4 to 14, preferably 4 to 6 or 8 carbon atoms, with a mono-olefin of 4 to 8 carbon atoms, preferably an iso-olefin of 4 to 5 carbon atoms. These rubbery copolymers may be made as described in U.S. Patent 2,356,128, and in the book by Wbitby on Synthetic .Rubber, l954,'chapter 24, namely by copolymerization at temperatures below 0 C., preferably between about :50 C. and -165 (3., preferably in the presence of cnce of a small amount of dissolved Friedel-Crafts catalyst, e.g. AlCl BF TiCl etc., dissolved in methyl chloride or ethyl chloride, or AlBr dissolved in heptane, etc. The resulting high molecular weight copolymer should have a Staudinger molecular weight of about 20,000 to 100,000 or more, corresponding to a viscosity average molecular weight of about 130,000 to 2,000,000, and should have a Mooney value (8 minutes at 212 F.) of about 30 to 90, preferably about 40 to 70, with a relatively low mole percent unsaturation of about 0.1 to 15%, or an iodine number (Wijs) of about 0.5 to 50. These copolymers, which have been manufactured commercially for a number of years under the Government designation GRI, are vulcanizable and may be cured either with some sulfur and older accelerators such as tetramethyl thiuram disulfide, mercaptobenzoyl thiazole, etc., or with non-sulfur curing agents such as paranitrosobenzene, paraquinonedioxime, or its derivatives, etc.

The above'described Butyl rubber is very diiferent in many respects from natural rubber which has an iodine number of about 350, and various high unsaturation synthetic rubbers such as GRS (butadiene-styrene emul sion copolymer), butadiene-acrylonitrile synthetic rubber, polychloroprene, and others which have iodine numbers ranging from about 200 to 350.

The proportions in which these modified pigments should be used will, of course, vary with the type of base stock and the intended use, but normally should be within the range from about 1 to about 150, preferably about .l0 to parts by weight per 100 parts of the liquid to solid base stock.

When the modified pigments are compounded with base stocks which are unsaturated the resultant composition is subject to further improvement by heat treatment applied to the mixture of modified pigment and Butyl rubber which may be carried out in several ways, namely, by hot milling, which is the preferred method, or by static heating followed by mastication, or by alternate cycles of static heating, e.g. for 15 minutes to an hour followed by a few minutes, e.g. l to 10 minutes, preferably about 3 to 5 minutes of milling or mastication. Such cycles may be repeated as often as desired, egg. 5 to 20 times, preferably about 6 to 10 or 12 times.

The temperature to be used may vary according to the type of heat-treatment being used and, of course, accord ing to the duration of heat-treatment. Generally, the temperature of the heat treatment should be from 250 to 450 F., preferably from 300 to 400 F., for a period of time ranging inversely according to the temperature, from about one hour to eight hours at 250 F. with static heating, to as short a time as 5 to 30 minutes at 350- 450 F. with hot milling, Banburying or other dynamic heating. Intermediate combinations of temperature time and amount of mastication or working may be used. In general, the time of heating (in hours) may be expressed by the formula:

where T is the temperature in F., and K is a constant of 15 to 600, preferably 40 to 550. Preferably, for static heating, K should be 200-550, and for dynamic heating, about 15 to 150.

Even in the case of static heating the heat-treatment must be followed by a final mastication to insure a homogeneous plastic composition which, either with or Without the further addition of curing agents, anti-oxidants, stabilizing agents, coloring agents, etc., may then be finally extruded into tubes, rods, etc., or calendered into sheets or films, or molded into the desired final shapes, with subsequent curing if the composition is unsaturated and has curing agents admixed therewith.

Although the mechanism of the operation of the invention is not known or understood in all respects, it is believed that one theory for the observed advantages of Hours the present. invention, which may particularly explain the emanate superior properties obtained after extended aging dfthe compositions produced according to theinvention, is that the cyclodiene radicals attached to the modified pigments are preferentially attacked by the oxygen coming in contact with the compositions, and that these cyclodiene ring structures break open without causing or permitting a break in the bond between the modified pigment and the unsaturated material with which it had been compounded and heat-treated, for instance, Butyl rubber. On the other hand, when other types of hydrocarbon-halosilane modified pigments have been made by prior art processes, the hydrocarbon radicals used were of such types as to be susceptible: to oxidation of a type permitting breaking of the bond between the modified pigment and the rubber or other material with which it had been compounded.

The objection and advantages of the invention will be better understood from consideration of the following experimental data.

EXAMPLE I Hi Sil C, hydrated silicon dioxide of fine particle size 25 millimicrons) has been treated .with cyclopentadienyl trichlorosilane and this product, along with standard (unmodified) Hi Sil C has been studied in natural and synthetic rubbers.

Standard Hi Sil C is hydroscopic. In conventional cyclic heat-treatment with open steam, its compounds absorb water so rapidly that they cannot be handled after only a few cycles. Treated Hi Sil C compounds absorb water much less rapidly and, whereas they can be cyclically heat-treated, it is believed that hydrolysis of the trichlorosilane groupings leads to undesirable results. Static heating in air or dynamic heating on a mill or in the Banbury are suitable methods for carrying out thermal interaction with these compounds.

Hi Sil pigments are very'fine particle size, precipitated, hydrated silicas. Their properties are listed below:

Hi SilC Ht'Stl Hi 811233 202 Bulk density 7:1:1 1b.]cu. it---. '8 lbs.'leu it Specific gravity 1.95 -i 1. 95 1.95. Average particle size millhnicrons 22 22. a oisturc 44% 5 5%. nH 8-9 7. 5 7.3. Refractive index 1.44 1. 46 1.46. Ignition loss 14% max 10 10%. 0a 86% 84 87. C210 3.0% 1.0 0.5. NaCL. 2.0% max. 1.0 1.0. Fe O 0.3% max 0.3 0.2. A1203 0.3% max 4. (J O. 6.

Hi Sil C was surface-treated with cyclopentadienyl trichlorosilane which was prepared in benzene solution by the following reaction:

no on Ho--0n Hii ('iH+SiGh- Hi'3 (BB-l-NaCl Na on ch S ick A portion of the product (6.8 gms) was dissolved in 2 liters of n-hexane and this solution was then poured over 200 gms. of Hi Sil C. The filter was hand-stirred in the liquid intermittently for 2 to 3 hours, after which time the n-hexane was allowed to 'evaporateat room temperature.

1 Butox ethyl diglycol carbonate. Tellurium diethyl dithi'ocarbamate. 3 3- anilinomethyl-2 (3) -benzothi-azolethlone.

vulcanizing' agents Were added and the compounds were cured over a range of times at 307 F. Table II shows the stress properties of these vulcanizat'es.

- ma I.-'-'-.S't-ress properties of butyl compounds containing standard and CPD SiClymodified 'Hi-Sil'C filler Modulus is increased 46% (on the average) and tensile strength is increased 400-500 lbs./in. when cyclopentadienyl trichlorosilane treated Hi Sil C is substituted for standard Hi Sil C in a conventionally mixed butyl compound. 'Normal Hi Sil C compounds cannot be cyc'li cally heat-treated with live steam because unmodified Hi Sil C is hygroscopic; and trichloro'silane groups on modified Hi Sil C may be hydrolyzed 'or polymerized in the presence of water.

EXAMPLE II The Example I described above was repeated in every detail except that half of each masterbatch"was subjected to thermal interaction in the form of milling for 40 minutes at 310 F. The attached drawing shows the stress properties of these vulcanizates. Hot milling with unmodified Hi Sil C in butyl leads to some modulus increases. The effect is more pronounced in the early cures, andthc similarity of the values at minutes suggests that heat treatment here does little more than accelerate the rate of vulcanization. Modified Hi Sil C systems give greatly increased values of modulus even in the absence of thermal interaction, and after heat treatment, modulus is even further advanced in these'compounds, the greatest changes occurring with the longest cures. Thus a significant thermal interaction effect is found and this efiect, when added to the improvements realized from using cyclopentad-ienyl trichlorosilanemodified Hi Sil C in conventionally mixed compounds, permits one to almost double the modulus previously obtained in this type of vulcanizate. Tensile strength is-likewise enhanced, as is shown by the data in Table 'II.

Table II.-Tensile properties of butyl-Hi Sil compounds before and after hot milling TENSILE-ELONGATION 300% MODULUS No Heat-Treatment t Heat-Treated 1 Test. N0 1 2 3 4 Standard Modified Standard Modified Hi Sil Hi Sil Hi S11 HiSil Cured at 307 F.

(minutes):

1 Hot milled for 40 minutes at 310 F,

, Dynamic property improvements are obtained by the present invention. One of the important changes is increased resilience. This property is measured in a free vibration apparatus using the modified, Yerzley oscillograph, as described in Rubber Age, vol. 67 (1951), page 51. An internal viscosity-frequency term, a is thus obtained. It represents the energy loss from damping and is inversely proportional to elasticity or resilience. The dynamic modulus, K, may also be calculated from this experiment. For the lowest hysteresis, it is desirable to have the internal viscosity low and the dynamic modulus high, and the ratio of these terms, K/w, yields the percent relative damping. These properties were measured at 50 C. with the present set of vulcanizates cured for 45 minutes at 307 F. a

Dynamic property tests on the same above are shown in Table III.

samples discussed Table III.-Dynamic propertiesfof butyl-H i Sil compounds before and after hot milling N o Heat-Treatment Heat-Treated 1 Standard Modified Standard Modified HiSilO HiSilG HiSilC HiSilU Test No- 1 2 3 4 mXmpolsesXc.p.s 2. 81 1. 48 2. 36 1. 39 KX10 drums/em? 8. 23 6.70 7. 96 6. 90 Percent relative damping. 24. 16. 2 21. 2 14. 9

1 Hot milled for 40 minutes at 310 F.

Table III shows that surface treatment of the pigment produces greatly improved dynamic properties in butyl compounds, and that thermal interaction, with either standard or modified Hi Sil C, has only a small effect. It is noteworthy, however, that in going from the conventional system (first column) to the twice modified system (fourth column), 1;, is reduced by 50% and the relative damping by almost 40%.

EXAMPLE III' Butyl-Hi Sil compounds may be thermally interacted by static heating in air and Table IV shows data taken from work in which the masterbatches were thermally interacted by heating them for four hours in an oven under air pressure at 80 pounds gauge at 320 F.

Table IV.-Tensile properties of butyl-Hz Sil compounds before and after static heating 'IENSILE-ELONGATION 300% .MODULUS statically heated, 80# air at 320 F. for 4 hours.

In general, these results are similar to those in the drawing and Table II. Exceptfor the change in heat treatment conditions, this Work employed the same procedure used in the'previous Example '11.

'As already stated, butyl vulcanizates prepared with non-black fillers are generally characterized by low modulus, and tensile strength is usually low in these compounds. In sharp contrast, one can, with cyclopentadienyl trichlorosilane modified Hi Sil C and thermal interaction, produce non-black butyl stocks with vulcanizate quality very nearly matching that which is normally obtained with channel black. For comparison, the results of Test 4 in Example II, are reproduced herebelow in Table Vwhich lists the tensile and dynamic properties of (1) a typical prior art non-black butyl compound, (2) a butyl compound thermally interacted with surfacetreated Hi Sil C, and (3) a butyl compound mixed conventionally with MPC channel black. The near approach to fwhite carbon black" (columns 2 and 3) is demonstrated in this work.

Table I.-An approach to "White Carbon Black" Test No 1 2 3 Filler Zeolex Modified M.P.O.

' 2D 1 H1 S11 0 Black Par ts oi filler/100 parts of polymer. 80 40 None None 45 45 1, 360 3.285 3, 300 300% modulus, lbs/in. 420 620 850 Percent elongation 670 690 63!) 1 x10 poisesxcps 3.0 1.4 3.3

1 Sodium aluminosilieate.

It is noteworthy that with Zeolex 20, as with most nonblack fillers in butyl, a high concentration of pigment is required to obtain significant values of modulus at 300% extension. Heat-treatment of this composition containing Zeolex produces no improvements in vulcanizate qualzty.

Though the CPD. silane-modified silica is outstanding in its applicability to Butyl rubber, it may be applied, though generally with less beneficial results, to the compounding of natural rubber and various high-unsaturation synthetic rubbers.

Among the high unsaturation rubbers, the invention appears most applicable to the diene-nitrile synthetic rubbers, as shown in the following data.

EXAMPLE IV HYCAR 03-25 (BUI'ADIENE-ACRYLONITRILE COPOLYMER RUBBER) Hycar compounds in this example were prepared according to the formulation given herebelow. Hycar 0R-25' is an emulsion copolymer of butadiene and 25% acrylonitrile.

HYCAR FORMULATION The Filler" used was Hi Sil C, either standard, or

. "Q modified reaction with 'C;P:D. triehlorcsilane as described in Example 1. Table VI summarized the results of stress-strain tests, and demonstrates the reactivity of this acrylonitrile co- The sharp'decre ases in extensibilityaccompanying the use of modified I-IiSil C in these systems suggest a process involving 'bonds strong enongh to limit the'mobility "of the polymer chains. "The dual reactivity "of 'Hycar is '20 Modlrg at,'1bs.'/in'.'=: -:borne-'ont again in the dynamic properties data given in I treatment) as a base, reduction in -1 may be obtained by using surface treated pigment, either without .heattreatment (column 2)., or with heat-treatment (column 4.). .It is interesting to note further :in these systems that, whereas the control vulcanizates are ,grey in color and opaque, the corresponding vulcanizates after heat-treat- .mentare red amber and translucent.

EXAMPLE V-NEOPRENE The modulus of neoprene GN 'vulcanizates is not greatly changed by substituting cyclopentadienyl triclilorosilane modified Hi Sil C for the standard filler but the tensile strength is increased by about The -celerators and for this reason heat-treatment leads only to scorching "and premature vulcanization.

EXAMPLE Compounds o'f'butyl with standard and surface treated Hi Sil C were prepared using the following formulation:

FORMULATION OF COMPOUND Butoxyethyl diglycol carbonate. Tellurium diethyl dithiocarbamate.

* 3-ani1in'omethyl-2 (3) benzothiazolethione.

Half of the rnasterbatch was set aside without further treatment.

The other half wasihotrmilled-for minutes at 310 F. Vulcanizing agents were added .finally on a -.cool mill and .the compounds were cured Lfor60minutes at 307 F.

Hi Sil C was surfaceitreated =with :cyclopentadienyil Table 'VI'I.

Table VII-Dynamic properties of Hy'car-Hi Sil compounds 25 N o Heat-treatment Heat-treated "Test No.. 1 f. v-2 3 4 Standard Modified Standard Modified.. HiSilO Hi snoHisno. Hiisno' 30.

mXltH, poisesXc.p.s 13 3. 29 3.00 2. 42 KX10- dynes/cmfi 13:4 10. s 9.80 9. 90 Percent relative damping--- 26. 6 21.7 21. 8 17. 8

Taking the first control (Standard Hi Sil -C., no heatpolymer may be cured in the absence of sulfur and ace *rrfic hlorosilane. Varying amounts' oi the silane were dis- :sdlved inn-liter portions of n-h'exane and t hese 'solut'ions were ponredover ZOO-gram lets of th'e pigment. The latter were s'tirr'efl tot-"2 to 3 hours, after which the servers was allowed ie-"evaporate ofi--"a't "room temperature. Table VI' II gives the physical properties -Tot -=butyl vulcanizates prepared with fhe resulting filiers. A "control in each series shows the properties which are' obtained with standard Hi 'Sil C. Data are presented ior aIl of the system, both before and after heat treatrnent.

Table VIII.Physical properties of .butyl rubber com pounds with eyc lape'ntadienyl 'rrichlvrosilane medified Hi Sil C NOT HEAT-TREATED Test No 1 2 4 5 Weight P cent Qyclopent'adienyl Triehlorosilane.-. 0 -.1 6 10 155 190 E 200 =-175 150 200%. :220 265 300 276; #275 30 295 375 440 {440; A60 400? 425 550 670 675 725 500%-" e50 935 1, 1, 08]) 1,105 60 1,380 1,600 1,775 1,670 1,775 700 2, 2, 250 2, 450 2,361 2,520 Tensile strength, lbs/m 2, 500 2, 415 2, 530 2, 750 2, 900 Percent elongation 755 715 720 770 770 nrXlO-t, p0ises c.p;s 4. 09 3. 25 2. 63 1. 943 1. 91 K 10- d mes/c1112-- 8.95 8. 30 8. 33 6. 78% 6. 30 Percent relative dampin 30.9 27.1 22. 4 20. 5; 21.6

HEAT-TREATED Test No...v 6 '7 8 9 10 Weight Percent Cyclopen- I tadienyl Trichlorosilaue--. 0 1 B 6 #10 Modulus at, lbs/in Y l00f7-- 150 180 .165 200%. 200 290 350 370 350 300%-" 310 '450' '590 '675' 690 400%- 470 725 1, 000 1,150 I l, 225 500""- 825 1, 250 1, 660 1, 825 1, 940 600%- 1, 550 2,- 040 2, 430 2, 575 2, 650 700%- v 2, 335 2, 600 'Tensiles'trength,'lbsf/infi. 2, 700 2, 700 2, 725 2,950 2, 950 Pereenflelongation 765 710 665 665 .665 rXIO- poisesXe.p.s 2. 07 2. 12 1.-82 1-56; 1. .42 K' 1O- dynes/cm. ,'-50 0-- 6109' 6. 68- "6. 59 6.12 5. 60 Percentmelativedamping-0; 24:0 22.5 19.19 t .18. 5 18.14

'The extension modulus of the vulcanizate is increased as the sur face modification of the pigment :is carried mp to about '6 "weight percent :of =cyclopentadienyl trichloro- 'silane. Heat-treatment, exceptin the case of the :system with standard .Sil =C,1eads to additional sharp 9increa'ses in modulus. This response 'to heattreatment is .a maximum also :in the nei'glt'borhood of 6% modification on the .filler. :It is evident hem the data in Table I that the damping properties of butyl'HiSil C systems are greatly improved i'f the pigment is :surface treated 'with cyclopentadienyl trichlorosilane. m, an inverse resilience term which measures theenergydoss from damping (see articl'e by P. =Baldwin in Rubber Age, v. 6? (1951 p.:5 1:), is decreased as much as 50%. Heat-treatment brings about -a further enhancement of the damping properties, but there'sponsein this :case becomes slightly less as the modification on the pigment-is increased. It appears to reach a minimum (optimum with filler containing about 61% of the silane. This :is an unexpected result for which no immediate explanation can be given.

:If one treats Hi Sil C with cyclopen'tadienyl"tri-isoipropoxysilane, th'e'pigment does not become responsive to heat-treatment as it does when 'treated"with the corlre'sponding 'lralo'silane. Likewise, if one treats Hi i'SilC with ethyl 'trichloro'silane, the .pigment does not become responsive.

"FORiHEAT- TREATMENT .A rmasterbatch .was prepared vwith -:b.uty'l cuontai'ning standard Hi Si], C and Hi Sil C modified with 6 Wtnaper .cent of cyclopentadienyl trichlorosilane, respectively.

Each masterbatch was split into :three portions. No jadditionwas'made to the, first portion. To the second and third portions, 0.1 and 0.5 of p-quinonedioxime (G.M.F.) were added, respectively (weights taken on 100 of polymer). All portions were then .hot milled for 10 minutes at 310 F. 'Curing agents were added finally and the compounds were vulcanized as already described. Table IX shows the properties which were obtained from the resulting samples.

1Table IX.Physical properties of standard and modified Hi Sil C compounds heat-treated with quinonedioxime promoter p I Hi Si] with 6% Standard Hi Sil O Cyclopentadienyl Trichlorosilane Pigment Test No-.- 1 2 3 4 5 6 Parts oip-Quinonedioxlme per 100 parts of Polymer 0 0. 1 0. 5 0 0. 1 0. 5

Migld ulus at, lbs./

150 180 185 210 275 370 370 605 500 675 730 1, 815 855 E 1, 150 1. 255 2, 160 1,360 1, 825 2, 000 2, 990 2, 030 2, 575 2, 760 i 2, 675 Tensile strength,

lbs/in. 2, 540 2,835 2, 950 3, 040 2, 900 Percent elongation 755 740 665 6 50 XliH, poisesX s 2. 07 1. 56 1. 44 0. 91 KX10- dynesl 6.09 6.12 5.98 5. 57 Percent relative damping 2-1. 0 18. 5 17. 5 12.3

1 Scorched.

Without promoting agent, little or no change in modulus results from the heat-treatment of butyl-standard Hi Sil C systems. Some response is obtained if 0.1 part of quinonedioxime is included in the'masterbatch (Table IX). With 0.5 part of the dioxime, the batch scorches in a very few minutes on the hot mill. The band first becomes rough. Then it laces and bags, and finally crumbles so that it can no longer be forced around the mill roll. Compounds with cyclopentadienyl trichlorosilane do not scorch, at least at the quinonedioxime concentrations shown in Table IX. With 0.5 part of the'rpromoting agent, the modulus of the resulting vul- .canizate approaches that of a heat-treated channel black tread compound. It has equivalent tensile strength and extensibility, but much lower hysteresis or. damping prop- ,erties. Thedamping' properties of this Hi Sil system are in the same range-as-those of a good, thermally inter- .acted butyl carcass compound with 35 parts of channel black and plasticized with 12.5 parts of oil.-. Column one in Table X relists the properties of the cyclopentadienyl trichlorosilane modified Hi SilC-compoundheattreated with 0.5 part of p-quinonedioxime (last column of Table IX.) Columns two and three in Table X list .similar properties for a-butyl tread (50 parts ofchannel black and 3 parts of oil) and a butyl carcass (30 parts of channel black and 12.5 parts of oil), respectively. These the compounds were thermally. interacted in the Banbury using Polyac (p-dinitrosobenzene) as -the. promoting .agent. Forum 40, an acid-treated parafiinic petroleum distillate, was the oil employed as plasticizer. Itcanbe seen from the comparison in Table X that it is possible with pigment modification and promoted heat-treatment "to prepare from Hi Sil C a butyl compound combining the strength and modulus characteristics of a tread stock, and'he resilience or hysteresis characteristics of a. carcass -stcc formula 12 Table X.-+Comparison of Hi Sil C compound with buty tread and carcass compound Channel Black and Oil Plastic-1 er- OPD-TGS Parts of Oil Modified Hi Sil C X p Test N o 1 2 3 Modulus at, lbs/in 210 260 150 200 605 725 325 300 1, 315 1, 420 580 400%--- 2, 160 2, 1, 500% 2, 900 2, 750 1, 730 Tensile strength, lbs/i113- 2, 900 2, 750 l, 935 Percent elongation. 500 500 500 m 10-, DOISGSXO-D. 0,91 2.00 0. 59 KXltH, dynes/cm.= 5. 57 6. S2 4. 06 Percent relative damping. 12. 3 21. 0 11.0

1H1 Sil o compound-Test No. 0 in Table IX. I i

It is not intended that this invention be limited to th specific modifications or examples which have been given merely for the sake of illustration, but only by the appended claims in which it is intended to claim all novelty inherent in the invention of modifications coming within the scope and spirit of the invention. i

What is claimed is:

1. As a new product, a mineral pigment consisting of at least partially hydrated silica, reacted with a cycloalkadiene-substituted chlorosilane having the general in which R is a cycloaliphatic dienyl radical having} to 6 carbon atoms in the ring, m equal to 1 to 2n+1, and 11:1 to 5.

2. As a new product a hydrated silica reacted with cyclopentadienyl trichlorosilane.

3. Composition comprising 100 parts by weight of: rubbery isoolefin-multiolefin copolymer having an iodine number (Wijs) of 0.5 to 50 and homogeneously admixed therewith about 10 to 100 parts by weight of the reaction product of cyclopentadienyl trichlorosilane with hydrated silica.

4. The method of making improved surface-reacted mineral fillers which comprises making a solution of cyclopentadienyl trichlorosilane in n-hexane, using proportions corresponding approximately to 6.8 gms. of the silane and 2 liters of hcxane,.and then mixing a precipitated hydrated silica of fine particle size therewith, in proportions corresponding approximately to 200 gms. of the silica per 6.8 gms. of said silane, stirring the resulting mixture of silica in the silane-hexane solution intermittently for 2-3 hours, and then evaporating the hexane.

5. The method of making improved mineral pigments which comprises reacting the particles of a mineral pigment selected from the group consisting of oxides of silicon, aluminum and titanium, silicates of aluminum and calcium, carbonates of calcium and magnesium, and hydrated derivatives thereof, with a cyclodiene-substituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having 5 to 6 carbon atoms in the ring, and lower alkyl derivatives thereof;

6. Method according to claim 5, using'about l to 15 parts by weight of cyclodiene-substituted 'chlorosilane per 100 parts by weight of pigment. v

7. The method of making improved mineral pigments which comprises reacting the surface of particles of a hydrated silica pigment with about 1 to 15 parts by weight of cyclopentadienyl trichlorosilane per 100 parts of pigment.

8. The method of making improved mineral pigments which comprises reacting the surface of particlesof a hydrated alumina pigmentwith about '1 to 15 parts by weight of cyclopentadienyl trichlorosilane per 100 parts of pigment.

9. As a new product, a mineral pigment selected from the group consisting of oxides of silicon, aluminum and titanium, silicates of aluminum and calcium, carbonates of calcium and magnesium, and hydrated derivatives thereof, the particles of which have been reacted with a cyclodiene-substituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having to 6 carbon atoms in the ring, and lower alkyl derivatives thereof.

10. Product according to claim 9, using proportions of about 1 to parts by weight of cyclodiene-substituted chlorosilane per 100 parts by weight of pigment.

11. The method of making improved filler-rubber compositions which comprises homogeneously admixing 1 to 150 parts by weight of mineral pigment selected from the group consisting of oxides of silicon, aluminum and titanium, silicates of aluminum and calcium, carbonates of calcium and magnesium, and hydrated derivatives thereof, the particles of which have been reacted with a cyclodiene-substituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having 5 to 6 carbon atoms in the ring, and lower alkyl derivatives thereof, with 100 parts by weight of an unsaturated vulcanizable rubber selected from the group consisting of natural rubber, butadiene-styrene copolymer synthetic rubber, polychloroprene, butadieneaerylonitrile copolymer rubber, and olefin-multiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 50.

12. The method of making improved compositions of isoolefin-multiolefin copolymer rubber and mineral filler, which comprises homogeneously admixing about 10 to 100 parts by weight of hydrated silica pigments, the particles of which have been reacted with a cyclodienesubstituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having 5 to 6 carbon atoms in the ring, and lower alkyl derivatives thereof, with 100 parts by weight of isoolefinmultiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 50.

13. Process according to claim 12. followed by subjecting the resulting mixture of reacted silica pigment and isoolefin-multiolefin copolymer rubber to heat treatment at a temperature between about 250 and 450 F. inversely for 8 hrs. to 5 minutes, to promote the formation of bonds between the reacted silica pigment and the isoolefin-multiolefin copolymer rubber.

14. Process according to claim 13 in which said heat treatment is carried out in the presence of a heatinteraction promoter from the group consisting of quinone and nitroso compounds.

15. The method of making improved compositions of isoolefin-multiolefin copolymer rubber and silica pigment which comprises homogeneously admixing about 10 to 100 parts by weight of a hydrated silica pigment, the particles of which have been reacted with about 3 to 10 parts by weight of'cyclopentadienyl trichlorosilane per 100 parts of hydrated silica, with 100 parts by Weight of isoolefin-multiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 50, and with about 0.5 part by weight of paraquinone dioxime as a heat interaction promoter, then subjecting the resulting mixture to a heat treatment comprising hot milling the mixture at about 310 F. for about 10 minutes.

16. Composition comprising 100 parts by weight of a material selected from the group consisting of natural i4 rubber, butadiene-styrene copolymer synthetic rubber, polychloroprene, butadiene-acrylonitrile copolymer rubber, and isoolefin-multiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 5G, polystyrene, polyethylene, polyvinyl chloride, and styrene-isobutylene copolymers, and homogeneously admixed therewith about 1 to 150 parts by weight of a mineral pigment selected from the group consisting of oxides of silicon, aluminum and titanium, silicates of aluminum and calcium, carbon arcs of calcium and magnesium, and hydrated deriva= tives thereof, the particles of which have been reacted with a cyclodiene-substituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having 5 to 6 carbon atoms in the ring, and lower alkyl derivatives thereof.

17. The method of making improved vulcanized fillermbber compositions which comprises homogeneously admixing 1 to 150 parts by weight of mineral pigment selected from the group consisting of oxides of silicon, aluminum and titanium, silicates of aluminum and calcium, carbonates of calcium and magnesium, and hydrated derivatives thereof, the particles of which have been reacted with a cyclodienesubstituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having 5 to 6 carbon atoms in the ring, and lower alkyl derivatives thereof, with parts by weight of an unsaturated vulcanizable rubber selected from the group consisting of natural rubber, butadiene-styrene copolymer synthetic rubber, polychloroprene, butadiene-acrylonitrile copolymer rubber, and isoolefin-multiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 50, also admixing therewith vulcanizing amounts of vulcanizing agents, and heating to effect vulcanization.

18. Composition comprising improved filler-rubber vulcanizates of a homogeneous admixture of vulcanizing agents with 100 parts by weight of an unsaturated vulcanizable rubber selected from the group consisting of natural rubber, butadiene-styrene copolymer synthetic rubber, polychloroprene, butadiene-acrylonitrile copolymer rubber, and isoolefin-multiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 50, and homogeneously admixed therewith about 1 to parts by weight of a mineral pigment selected from the group consisting of oxides of silicon, aluminum and titanium, silicates of aluminum and calcium, carbonates of calcium and magnesium, and hydrated derivatives thereof, the particles of which have been reacted with a cyclodienesubstituted chlorosilane, in which said cyclodiene is selected from the group consisting of cycloalkadienes having 5 to 6 carbon atoms in the ring, and lower alkyl derivatives thereof.

19. Composition comprising improved vulcanizates of isoolefin-multiolefin copolymer rubber and mineral filler, comprising vulcanizates of a homogeneous admixture of vulcanizing agents with 100 parts by weight of isoolefinmultiolefin copolymer rubber having an iodine number (Wijs) of 0.5 to 50, and about 10 to 100 parts by weight of hydrated silica filler the particles of which have been reacted with about 3 to 10 parts byweight of cyclopentadienyl trichlorosilane per 100 parts by weight of hydrated silica.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AS A NEW PRODUCT, A MINERAL PIGMENT CONSISTING OF AT LEAST PARTIALLY HYDRATED SILICA, REACTED WITH A CYCLOALKADIENE-SUBSTITUTED CHLORSILANE HAVING THE GENERAL FORMULA 